Adaptive Projection Television Screen Mounting Clamps

ABSTRACT

Strip mounts on the top and bottom screen mounting brackets for holding a projection display screen in place while accommodating screen tolerances are disclosed. The strip mounts have a C-shaped profile that holds the display screen in place. The screen mounting brackets are elongate, stiff members.

FIELD OF THE INVENTION

The invention relates generally to a projection display and, inparticular, details for mounting a projection display screen.

BACKGROUND OF THE INVENTION

Projection display televisions have become widely used. The cabinets forthese projection display televisions are typically made from plastic. Aproblem that projection display televisions typically have is keepingthe top edge of the screen straight and in the proper location. Plasticcabinets provide nice aesthetics but have a tendency to bow along thetop edge, aggravating the ability to keep the top edge of the screenstraight and in location. This is an even more severe problem onprojection display televisions that incorporate upangle optics becausesuch televisions require a more accurate screen location with respect tothe optics.

Many projection televisions have a problem mounting the screen becauseof large dimensional tolerances and variations. A particular problem isthe thickness tolerance of the screen. The screen is typically made upof multiple pieces that are laminated and/or taped together. Anotherproblem is that the width and height of the screen may varysignificantly as a function of temperature and humidity. The screen mustbe free to expand in width and height or it will bulge out. With thesteep upangles involved in recent projection televisions, bulging of thescreen can cause significant image distortions. Typically, these screensare held in a groove in metal wood or plastic. The groove has room forexpansion and contraction of the screen and mating parts. The sloppy fitis acceptable for conventional projection television displays andon-axis microdisplay sets since the resulting image geometry is notdistorted. However, with the steep upangles associated with recentprojection display raypaths, changes in the location or position of thescreen surface results in significant distortions to the image geometry.

SUMMARY

The present invention provides strip mounts to the top and bottom of thescreen mounting brackets to hold a projection display screen in placewhile accommodating screen tolerances. The strip mounts have a C-shapedprofile that holds the display screen in place. The screen mountingbrackets are elongate, stiff members.

BRIEF DESCRIPTION OF THE DRAWINGS

Exemplary embodiments of the present invention will next be describedwith reference to the accompanying figures, of which:

FIG. 1A is a prospective front view of a projection display televisionaccording to an exemplary embodiment of the present invention;

FIG. 1B is a prospective rear view of the projection display televisionof FIG. 1A;

FIG. 2 is a partial rear perspective view of the projection displaytelevision of FIGS. 1A and 1B, showing the top extrusion according to anexemplary embodiment of the present invention;

FIG. 3A is an exploded side-view of the plastic screen frame, extrusionsand strip mounts;

FIG. 3B is a sectional view of the plastic screen frame, extrusions andstrip mounts of FIG. 3A; and

FIG. 3C is a sectional view of the extrusion and strip mount of FIG. 2.

DETAILED DESCRIPTION

The present invention, shown in FIGS. 1A-3C, provides an extruded metalhinge mechanism that keeps the top of the projection display televisionscreen frame straight and allows the screen assembly to be removed fromthe front without the use of screws from the rear.

An exemplary projection display television is shown in FIGS. 3A-3C. Thescreen mounting bracket 50 has top and bottom aluminum extrusions, thatare a continuous stiffener for the screen frame 12. Aluminum extrusionsare inexpensive to fabricate and provide good dimensional stability andstiffness properties. Strip mounts 55A, 55B attached to the top andbottom screen mounting bracket 50 are used to hold a projection displayscreen 10 in place.

The screen mounting bracket 50A comprises: an anchoring portion 51 thatattaches to the screen frame 12 and a “T” shape detail 56 to accept thestrip mount 55. In an exemplary embodiment, the anchoring portion 51conforms to projections and/or recesses in the screen frame 12 to form apress fit with the screen frame 12.

Strip mount 55A is attached to the “T” shape detail 56 of the screenmounting bracket 50A, while strip mount 55B is attached to the “T”details 56 of the screen mounting bracket 50B. In an exemplaryembodiment, the strip mounts 55A, 55B have a C-shaped profile and may bemade of a flexible plastic extrusion. When mated with the screen frame12, there is space between the convex portion of the extrusion and theframe to accommodate the screen thickness. The profile of the stripmounts is such that C-shaped cross section allows the profile to flexand maintain a preload against the screen. The strip mounts 55A, 55B arecontinuous and evenly press against the screen 10.

The top and bottom screen mounting brackets 50A, 50B are metalextrusions that have a mating “T” shape detail 56 (FIG. 3C) to capturethe strip mounts 55A, 55B. This mating detail 56 is such that the stripmounts 55A, 55B squeezes the metal extrusion. When there is pressureagainst the strip mounts 55A, 55B, the C-shape opens up allowing theheight of the extrusion to collapse as needed to accommodate the screenthickness variation while maintaining a reasonable force. The plastic orelastomeric material used for strip mounts 55A and 55B is chosen to bechemically compatible with the screen 10 materials and to have surfacehardness characteristics that prevent abrasion to the screen materialsduring shipping and vibration. Linear protrusions 58 incorporated in thestrip mounts 55 act as “light strips” to reduce reflections of unwantedlight onto the screen 10. A similar result could be obtained by havingmultiple small striations incorporated into the side wall of the stripmounts rather than the larger linear protrusions.

The screen mounting bracket 50A, 50B and the strip mounts 55A, 55Bextend essentially the length of the elongate direction (i.e., entirewidth of the screen frame 12), stiffening the entire top edge of thescreen frame 12, holding the top edge of the screen 10 straight and inthe proper location.

The cabinet may be plastic, as is typical for projection displaytelevisions. When mounted to a plastic cabinet, these brackets 50, inthe form of extrusions, form a low profile, structural member along thetop edge of the cabinet 20. This structural member can be tied intoother structural members of the cabinet 20 to help maintain the criticallocation of the screen frame 12. Along with being very low cost to tool,aluminum extrusions tend to be inherently straight, stiff and stable ascompared to other parts such as plastic extrusions, formed sheet metal,wood, or molded plastic.

The foregoing illustrates some of the possibilities for practicing theinvention. Many other embodiments are possible within the scope andspirit of the invention. For example, while the exemplary embodimentshows aluminum extrusions for the structural members, the concept isalso applicable with roll formed sheet metal or sheet metal parts madeon progressive dies. It is intended, therefore, that the foregoingdescription be regarded as illustrative rather than limiting, and thatthe scope of the invention be given by the appended claims together withtheir full range of equivalents.

1. A bracket for mounting a projection display screen to a cabinet fromthe front of the screen, comprising: a screen bracket attached to ascreen frame having the screen mounted thereto; and a strip mount,wherein the strip mount is attached to the screen bracket and touchesthe screen.
 2. The bracket of claim 1 wherein the screen bracket iscontinuous.
 3. The bracket of claim 2 wherein the screen bracket has aconstant cross section along the elongate dimension.
 4. The bracket ofclaim 1 wherein the strip mount and the screen bracket are extrusions.5. The bracket of claim 1 wherein the screen bracket is formed ofaluminum.
 6. The bracket of claim 1 wherein the strip mount is C-shaped.7. A projection display, comprising: a cabinet; a screen mounted in ascreen frame; and bracket for mounting the screen frame, wherein thebracket has a strip mount attached thereto and touching the screen. 8.The projection display of claim 7 wherein the bracket is continuous. 9.The projection display of claim 8 wherein the bracket has a constantcross section along the elongate dimension.
 10. The projection displayof claim 7 wherein the strip mount and the bracket are extrusions. 11.The projection display of claim 7 wherein the bracket is formed ofaluminum.
 12. The projection display of claim 7 wherein the strip mountis C-shaped.